The present invention relates to a fine adjustment mechanism for a tool and, more particularly, to a fine adjustment mechanism for a table saw fence assembly.
Conventionally, many tools have a laterally slidable adjustment means to provide maximum versitility in use. The adjustment means commonly includes corresponding tracks and guides slidable thereon together with means for releaseably securing the guides on the tracks in selected positions of adjustment. Unfortunately, it is usually very difficult to make fine adjustments with any degree of accuracy.
In the case of a table saw, the saw is typically provided with a pair of substantially parallel spaced apart tracks extending substantially transversely of a normal cutting direction. A fence assembly having an elongated fence extending between the tracks and substantially transversely of the tracks is usually provided so as to be substantially parallel to the normal cutting direction. Additionally, the fence assembly may typically include a pair of fence guides each of which is adapted to engage one of the tracks for sliding movement therealong.
As with other tools having a laterally slidable adjustment means, it is generally recognized that, at best, fine adjustments in the position of the fence are difficult to make. There has, in fact, been a long felt need for an improvement in table saws making it possible to accurately position the fence by making fine adjustments in its position in a minimum of time and without the difficulties presently encountered. Despite the recognition of this need, there has been no truly effective means for making fine adjustments in the position of a table saw fence.
There have been many attempts to overcome the perceived problems in fine adjustment means for tools of various types. Lonskey et al U.S. Pat. No. 2,273,715 and Boker U.S. Pat. No. 2,018,831 disclose hand rotatable means for adjusting the position of a slide block laterally with respect to a cutting device whereas Mattison U.S. Pat. No. 2,267,937 proposes the use of a set screw to laterally fix the fine position of a slide block after initial adjustment has been made. Additionally, Gaskell U.S. Pat. No. 2,806,493 proposes an adjustable table saw fence assembly utilizing rack and pinion means.
Modderman U.S. Pat. No. 2,556,548, Musselman U.S. Pat. No. 2,521,302 and Gaskell U.S. Pat. No. 2,677,400 propose various types of conventional table saw fence assemblies while Hedgepeth U.S. Pat. No. 2,075,282 proposes the use of a drive wheel operatively joined to a hand knob for making position adjustments in a fence assembly for a table saw.
Despite the prior attempts to provide for fine adjustment of a table saw fence assembly, it has remained to do so in an effective manner so as not to impede gross adjustment. It has also remained to do so in a manner accommodating very fine adjustment with a minimum of force and without the need to depart substantially or completely from conventional fence assembly construction. Accordingly, the present invention is directed to overcoming the above stated problems and accomplishing the stated objects.